This invention relates generally to the generation of refrigeration and the provision of the refrigeration by direct contact with a heat source.
Refrigeration to provide cooling and/or freezing duty to a heat source is widely required in industrial processes such as in the cooling of exothermic reactors and the cooling of crystallizers. This refrigeration may be provided by indirect heat exchange of the refrigerant with the heat source. Direct contact heat exchange of the refrigerant with the heat source is advantageous because the heat exchange is more efficient than indirect heat exchange but such direct contact heat exchange adds complexity to the system. Moreover conventional direct contact refrigeration provision systems are characterized by high costs to generate the requisite refrigeration.
Accordingly, it is an object of this invention to provide an improved method for providing direct contact refrigeration wherein the requisite refrigeration may be generated with lower power costs than conventional systems.
The above and other objects, which will become apparent to those skilled in the art upon a reading of this disclosure, are attained by the present invention one aspect of which is:
A method for providing direct contact refrigeration comprising:
(A) compressing a multicomponent refrigerant fluid comprising at least two components from the group consisting of hydrocarbons having from 1 to 6 carbon atoms, fluorocarbons having from 1 to 6 carbon atoms, and inert gases;
(B) cooling the compressed multicomponent refrigerant fluid, expanding the cooled compressed multicomponent refrigerant fluid to generate refrigeration, and warming the refrigeration bearing multicomponent refrigerant fluid by indirect heat exchange with said cooling compressed multicomponent refrigerant fluid and also by indirect heat exchange with clean direct contact refrigerant to produce cold direct contact refrigerant;
(C) contacting the cold direct contact refrigerant with a heat source to cool the heat source producing warmed direct contact refrigerant which contains contaminants from the heat source; and
(D) treating the direct contact refrigerant to remove contaminants and to produce clean direct contact refrigerant for indirect heat exchange with the refrigeration bearing multicomponent refrigerant fluid.
Another aspect of the invention is:
Apparatus for providing direct contact refrigeration comprising:
(A) a multicomponent refrigerant circuit comprising a compressor, a heat exchanger, an expansion device, means for passing multicomponent refrigerant fluid from the compressor to the heat exchanger, from the heat exchanger to the expansion device, from the expansion device to the heat exchanger, and from the heat exchanger to the compressor;
(B) a heat source, means for passing direct contact refrigerant to the heat exchanger, and means for passing direct contact refrigerant from the heat exchanger to the heat source;
(C) a cleaning device, means for passing direct contact refrigerant from the heat source to the heat exchanger and means for passing direct contact refrigerant from the heat exchanger to the cleaning device; and
(D) means for passing direct contact refrigerant from the cleaning device to the heat exchanger.
As used herein, the term xe2x80x9cindirect heat exchangexe2x80x9d means the bringing of two fluids into heat exchange relation without any physical contact or intermixing of the fluids with each other.
As used herein, the term xe2x80x9ccontaminantsxe2x80x9d means one or more substances which will adulterate the direct contact refrigerant used in the method of this invention.
As used herein, the term xe2x80x9cinert gasesxe2x80x9d means nitrogen, carbon dioxide and noble gases such as helium and argon.